Nitrogen mustard alkylating agents are an important class of anticancer drugs, which express their cytotoxic and antitumour effects by cross-linking cellular DNA (Garcia et al., Biochem. Pharmacol., 1988, 37, 3189).
We have found that novel cobalt complexes of nitrogen mustard alkylating agents have hypoxia-selective antitumour properties and are therefore useful as antitumour agents.